From a475acf01f79e89a1a5845733e10108d80f77188 Mon Sep 17 00:00:00 2001 From: Seth Forshee <seth.forshee@canonical.com> Date: Tue, 26 Apr 2016 14:36:25 -0500 Subject: [PATCH] fs: Refuse uid/gid changes which don't map into s_user_ns Add checks to notify_change to verify that uid and gid changes will map into the superblock's user namespace. If they do not fail with -EOVERFLOW. This is mandatory so that fileystems don't have to even think of dealing with ia_uid and ia_gid that --EWB Moved the test from inode_change_ok to notify_change Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> --- fs/attr.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/attr.c b/fs/attr.c index 25b24d0f6c881..dd723578ddce7 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -255,6 +255,17 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID))) return 0; + /* + * Verify that uid/gid changes are valid in the target + * namespace of the superblock. + */ + if (ia_valid & ATTR_UID && + !kuid_has_mapping(inode->i_sb->s_user_ns, attr->ia_uid)) + return -EOVERFLOW; + if (ia_valid & ATTR_GID && + !kgid_has_mapping(inode->i_sb->s_user_ns, attr->ia_gid)) + return -EOVERFLOW; + error = security_inode_setattr(dentry, attr); if (error) return error; -- GitLab